A new video appears to contradict statements made by Papua New Guinea and Australian authorities after a death at Manus camp even further.

Transcript

A new video published by Australian media shows security guards at Australia's Manus Island detention centre in Papua New Guinea attacking asylum seekers the night before a 23-year-old was killed in February.

The video, obtained by Fairfax media, appears to contradict statements made by Papua New Guinea and Australian authorities following the death of Reza Berati after two nights of clashes.

The morning after Mr Berati's death, Australia's Immigration Minister, Scott Morrison, said that the security firm G4S had utilised personal protection gear, but that no batons or other weapons were used - a statement the video footage shows to be false.

There are also images that show that no action was taken to isolate the scene of Mr Berati's killing before evidence was either compromised or completely cleared away. Other images show bullet holes at stomach level in the centre, which challenges the assertion that only warning shots were fired in the air by police.

G4S, which is no longer responsible for security at the centre, refused to be interviewed, saying it does not comment in detail on individual allegations, but it did offer a statement that said:

It is not G4S's role to investigate any crimes that may have been committed on Manus Island; that is the role of the PNG police, which has jurisdictional authority. We are and will continue to fully co-operate with all investigations and reviews by the governments of Australia and Papua New Guinea.

The spokesperson for the Asylum Seeker Resource Centre, Pamela Curr, says from the contact her organisation's had with asylum seekers at the centre, the evidence shows that the scene of Reza Berati's death was clearly compromised.

PAMELA CURR: We heard that the next day they'd cleaned up everything, all the bullet casings were picked up and quickly whisked away and the place where the murder of Reza had taken place was cleaned up, but as you can see the actual centre was in such a bad state of repair they couldn't fix everything.

Scott Morrison's office says the minister is awaiting the outcome of an independent review before commenting further.

But the Australian Greens Senator, Sarah Hanson-Young, says the interim report has been sitting on Mr Morrison's desk for weeks, and that the Australian government is desperate to cover up an incident on its watch.

SARAH HANSON-YOUNG: It's time that he released it, he's obviously trying to hide something. He knows far more than he's letting on. The government has been aware of the situation inside the Manus Island centre for months, they were warned over and over again. They ignored those warning signs and what we saw was the brutal killing of one young man and the injury of scores of others.

Senator Hanson-Young has initiated an inquiry by the Australian Senate to investigate February's events at Manus Island, and asylum seekers have been invited to give their accounts of the violence under parliamentary privilege. But this has struck a hurdle because the inquiry is unable to travel to Manus to investigate and interview because the Australian Senate has no jurisdiction in Papua New Guinea.

Sarah Hanson Young says that can be overcome, and is being used as an excuse by the government of Prime Minister Tony Abbott. She's calling on Australia's opposition leader, Bill Shorten, to throw his support behind the inquiry travelling to Manus.

SARAH HANSON-YOUNG: They think if they sit on the report long enough, if they clamp down on witnesses being able to speak out, if they continue to gag workers who were there on the night that all of this will go away. Well it won't go away. A young man was killed, many injured, Australia's international reputation is in tatters and it's time for Bill Shorten to come out and back a full, frank parliamentary inquiry which has to include the committee visiting Manus Island.

Pamela Curr says the story put up by the authorities following Reza Berati's death has crumbled since day one, and this latest revelation just dents their credibility further.

PAMELA CURR: Well and truly, the cat is out of the bag. We knew a few days after that attack that what had happened on that terrible night of the 16th and 17th was very much at odds with what the minister was telling us. The minister had to play catch up.

Ten weeks on from the clashes on Manus Island, no charges have yet been laid.